5 or 7 bounces seems to be a reasonable amount for 10 man. On the first one in particular you could maybe afford to go to 7 simply because he spawns it sooner (so the boss will have fewer stacks of his self buff). On later ones there is a significant delay before he spawns it (for the healers to top the raid off) and he builds up more stacks of his self buff before it starts bouncing.
My general recommendation for 10 man normal would be to just go to 5 bounces each time for consistency (ranged bounces it 3 times, melee twice). Because of the continual rampup of damage on the boss it is definately best to save Heroism/Bloodlust/Time Warp for a late point in the fight, probably the phase two that lands closest to the 1 minute remaining on the berzerk. This I'd recommend for a Normal Mode T12 group doing Normal Mode T13.
Also an important note, he doesn't do the cone drain attach unless the ball is on the court. So it is perfectly safe to stand in front of the boss when there isn't a ball out and have the tank turn the boss as soon as he starts channeling it. This also applies to after every phase 2 (it's safe to be in front of the boss until the ball is out).
"In anything, if you want to go from just a beginner to a pro, you need a montage." /w TankSpot WTB Montage for Raiders.